Compressed air-operated disc brake

ABSTRACT

The invention relates to a compressed air-operated disk brake comprising a brake caliper to which a compressed air cylinder can be attached via a flange and in which a turning lever can be pivoted by a plunger rod of the compressed-air cylinder. The inventive disk brake should be designed in such a way that the interior of the brake caliper is protected from the penetration of dirt and moisture when the compressed air cylinder has not yet been attached, in particular, during transport and storage. In addition, no additional working operations should be required for mounting the brake cylinder, and no parts need to be disposed of. According to the invention, a cover, which is closed at first, is placed in the flange opening of the brake caliper and is provided with specified rupture locations. Since the cover does not project beyond the outer surface of the flange, it does not impede the subsequent attachment of the compressed air cylinder. After mounting the compressed air cylinder, the cover is torn open along the weakened lines or the specified rupture locations by Extending the plunger rod.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a pneumatically operated disk brake having acaliper which straddles a brake disk and which, on one side, is equippedwith an application device having a swivellably disposed rotary leverengaging with the plunger rod of a compressed-air cylinder. The caliperis sealed-off by means of bellows surrounding the plunger rod, and, onthe side facing the compressed-air cylinder, the caliper has a flangebounding a flange opening, for the connection of the compressed-aircylinder.

The concerned pneumatically operated disk brake is preferably used forcommercial road vehicles. The compressed-air cylinder is fastened bymeans of threaded bolts to the flange of the caliper. The bellowssurrounding the plunger rod of the compressed-air cylinder preventmoisture or dirt that penetrates into the interior of the caliper,whereby the corrosion-susceptible actuating mechanism would be damaged.The bellows are designed such that they have a ring-shaped seal on theside facing the caliper. As a result, a sufficient sealing is achievedat the point of intersection between the compressed-air cylinder and thecaliper, but only when the compressed-air cylinder is mounted.

The compressed-air cylinder is not connected to the caliper by themanufacturer of the brake, but rather by an axle manufacturer during themounting of the axles or by a vehicle manufacturer when mounting theaxle equipped with the brakes on a commercial vehicle. This circumstanceis the result of the fact that the required size of the compressed-aircylinder can be determined only in these phases. This leads to the factthat the flange opening is only insufficiently covered during the entireshipping and transport of the disk brake from the brake manufacturer tothe axle manufacturer and possibly also to the vehicle manufacturer. Inthis case, attention should also be paid to the fact that the brakesequipped with the axles are frequently stored in the open air for anextended period of time. This results in the danger that water ormoisture may penetrate into the interior of the caliper and causecorrosion.

In practice, the flange opening is closed by a glued-on foil forprotecting the actuating mechanism. This prevents foreign bodies frompenetrating into the interior of the caliper, but provides no protectionagainst the entering of moisture, particularly when the axles equippedwith the brakes are stored in the open air. In addition, the glued-onfoil can very easily be destroyed. No solution is therefore achievedwhich meets the requirements existing in practice. If it is known thatthe axles equipped with the brakes are stored in the open air(outdoors), the flange opening of the caliper is normally closed off bya screwed-on plastic flange into which a sealing element is integrated.Although this sufficiently seals off the flange opening, this solutioninvolves considerable cost caused by the additional components as wellas by the mounting and demounting expenditures. In addition, the plasticflange must be disposed of or transported back to the brakemanufacturer.

Finally, it is known from International Patent Document WO 97/13987 toinsert a seal having a centric opening into the flange opening. In theinoperative position of the rotary lever, the latter comes in contactwith the seal, so that a sealing-off takes place. Relatively largepositional tolerances occur in the assignment of the sealing surface ofthe rotary lever to the sealing lip of the seal. As a result, thepenetration of moisture cannot be prevented very effectively. Inaddition, the dome-shaped receiving device for the plunger rod of thecompressed-air cylinder, which is situated in the rotary lever, isoutside the protected area, so that specifically this particularlysusceptible point will corrode if stored for an extended time period.Furthermore, during the mounting of the compressed-air cylinder,moisture may reach the interior of the caliper.

Based on the prior art known from International Patent Document WO97/13987, it is an object of the invention to design a pneumaticallyoperated disk brake such that the interior of the caliper and theactuating mechanism mounted therein, while the compressed-air cylinderis not yet connected, is protected against a penetration of dirt andmoisture during the transport and the storage. Also, if possible, noadditional operations should be required for the mounting of thecompressed-air cylinder and, furthermore, no components should have tobe disposed of or transported back.

According to the present invention, the above-mentioned object isachieved in that a covering cap, which is closed at first but hasdesired breaking points, is inserted into the flange opening of thecaliper.

As a result of the completely closed covering cap, which is insertedinto the flange opening, it is ensured also over a long period of timethat, even when the disk brake is stored in the open air, no dirt ormoisture will penetrate into the interior of the caliper because thecovering cap completely covers the flange opening. Because it isprovided with desired breaking points, the covering cap can be torn openalong these points. Although this could also take place before themounting of the compressed-air cylinder, the tearing-open takes place nolater than when the plunger rod of the compressed-air cylinder isextended for the first time. The operation of the disk brake is nothindered by the torn-open covering cap. Because it can remain in theflange opening, a disposal or return to the brake manufacturer iseliminated. After the mounting of the compressed-air cylinder, thering-shaped seal of the bellows seals off the caliper in the customarymanner.

It is particularly advantageous for the covering cap not to protrudewith respect to the outer surface of the flange because it does nothinder the mounting of the compressed-air cylinder.

Particularly advantageously, the covering cap is force-lockinglyinserted into the flange opening. Additional securing elements, whichwould cause mounting expenditures and costs, will then be eliminated.The restoring forces building up during the insertion effectivelyprevent the covering cap from falling-out out of the flange openingduring the transport of the disk brake. This force closure between theouter edge of the covering cap and the flange opening can be achieved ina particularly simple manner if the covering cap is made of an elasticmaterial, for example, of an elastomer or of an elastomer-type syntheticmaterial.

With respect to the manufacturing, the desired breaking points can bemost easily obtained if they are designed as a weakened line, forexample, in the form of indentations, notches or the like. Because,after the mounting of the compressed-air cylinder, the center area mustbe free for the plunger rod, it is expedient for the weakened lines toextend from the center of the circular covering cap radially toward theoutside, the weakened lines then being situated at a mutually identicalangular distance.

So that the covering cap is torn open only along the desired breakingpoints, it is provided that the covering cap has a ring-shaped elevationadjoining the ends of the desired breaking points facing the outercircumferential surface. This elevation should be understood in thesense of a reinforcement. To ensure that the outer edge of the coveringcap is extremely stable, it is provided that this edge area has aU-shaped construction and that a metallic reinforcing ring in insertedtherein. This metallic reinforcing ring has an angled cross-section sothat its web, extending toward the center of the cap, reaches behind aring-shaped attachment of the cap. For ensuring that the covering capwill not hinder the mounting of the compressed-air cylinder, thecovering cap is arranged within the flange opening with respect to theouter surface of the flange in the direction of the brake disk.

The invention will be explained in detail by means of the attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of the covering cap which is inserted intothe flange opening of the caliper in which is arranged the rotary lever;

FIG. 2 is a perspective top view of the covering cap;

FIG. 3 is a sectional view taken along Line III—III in FIG. 2;

FIG. 4 is a sectional view of the compressed-air cylinder mounted on theconnection flange of the caliper and coupled with the rotary lever.

DETAILED DESCRIPTION OF THE DRAWINGS

For the purpose of a simplified illustration, the pneumatically operateddisk brake, as a whole, is not illustrated in the figures.

FIG. 1 shows that the outlined caliper 10 has a flange 11 for, accordingto FIG. 4, connecting a compressed-air cylinder 12 thereto. A rotarylever 13 is swivellably disposed in the caliper 10 by means of a bearing14 not explained in detail. A covering cap 16, which is explained ingreater detail by means of FIGS. 2 and 3, is inserted in the flangeopening 15 in a closing manner. As shown in FIGS. 1 to 3, the coveringcap 16 is closed with respect to its entire surface in the illustratedcondition. This condition exists when, in contrast to the representationaccording to FIG. 4, the compressed-air cylinder 12 is not yet connectedto the flange 11 of the caliper 10. In the illustrated embodiment, thecovering cap 16 is provided with five weakened lines 17, each forming adesired breaking point. The weakened lines 17 are formed byindentations. The weakened lines 17 extend from the center of thecircular covering cap 16 in the direction of the outer edge. They arealso situated at an identical angular distance from one another.

A ring-shaped elevation 18, which may be considered as a reinforcement,adjoins the outer edges assigned to the circumference of the coveringcap 16. The outer edge of the covering cap 16 has a U-shapedcross-section design. In this case, the open side of the U-shapedcross-section points in the direction of the brake disk, which is notshown, when the covering cap 16 is inserted in the flange opening 15. Ametallic reinforcing ring 19 is inserted into this outer edge, whichreinforcing ring 19 has an angled cross-section and whose leg, pointingtoward the center of the cap 16 reaches behind a ring-shaped attachment20. The covering cap 16 is made of an elastic material, preferably anelastomer or an elastomer-type synthetic material.

Of the actuating mechanism (brake application device) installed in thecaliper 10, FIGS. 1 and 4 show only the rotary lever 13. On the sidefacing the compressed-air cylinder 12, this rotary lever 13 is providedwith a dome-type recess 21, which is situated in the contour of theflange opening 15. The assigned, correspondingly designed end of atwo-part plunger rod 22 engages in this dome-shaped recess 21. Thecompressed-air cylinder 12 consists essentially of the two housing parts12 a, 12 b, of a membrane 23 clamped between the partition line, ofbellows 24 surrounding the plunger rod 22, and of a restoring spring 25.By means of the membrane 23, the housing formed of the housing parts 12a and 12 b is airtightly divided into two chambers. The outer chamberfacing away from the caliper 10 is equipped with a compressed-airconnection 26. For the perfect sealing-off of the interior of thecaliper 10, the facing end of the bellows 24 is designed in the mannerof a seal which reaches in a U-shape around the edge of a housing part12 a bounding an opening.

The manufacturer of the pneumatically operated disk brake supplies thecaliper in the condition illustrated in FIG. 1; that is, thecompressed-air cylinder 12 is not yet connected to the flange 11. Thecovering cap 16, which is closed in itself, hermetically seals off theflange opening 15, so that, also in the case of an extended storage inthe open air, neither dirt particles nor moisture can penetrate into theinterior of the caliper 10. FIG. 1 illustrates that no additionaloperations are required for the mounting of the compressed-air cylinder12, because the covering cap 16 remains in the flange opening 15.Although, during the mounting, the covering cap 16 can be torn openalong the weakened lines or weakened zones 17, it is not required thatthis take place any sooner than when the plunger rod 22 has moved-out(been extended). The covering cap 16 does not interfere with the furtheroperation of the pneumatically operated disk brake. In the embodimentaccording to FIG. 1, the flange 11 is inclined relative to a verticalline, while, in the embodiment according to FIG. 4, it extends in thevertical direction.

The invention is not limited to the illustrated embodiment. It isimportant that the covering cap 16 be inserted into the flange opening15 so it does not hinder the subsequent mounting of the compressed-aircylinder and that, no later than during the start of the operation ofthe disk brake, the covering cap is torn open along desired breakingpoints.

What is claim is:
 1. Pneumatically operated disk brake having a caliperwhich in use straddles a brake disk and which, on one side, is equippedwith an actuating mechanism having a swivellably disposed rotary leverengaging with a plunger rod of a compressed-air cylinder, the caliperbeing sealed off via bellows surrounding the plunger rod, and, on theside facing the compressed-air cylinder, the caliper having a flangebounding a flange opening, for mounting the compressed-air cylinder,wherein a covering cap is inserted into the flange opening of thecaliper, the covering cap being initially closed to seal-off the flangeopening, prior to the plunger rod engaging with the rotary lever, andhaving desired breaking points arranged therein.
 2. Pneumaticallyoperated disk brake according to claim 1, wherein the covering cap ismade of an elastic material.
 3. Pneumatically operated disk brakeaccording to claim 2, wherein the elastic material is one of anelastomer and an elastomer-type synthetic material.
 4. Pneumaticallyoperated disk brake according to claim 1, wherein the desired breakingpoints are formed by weakened lines, which extend from a center area ofthe covering cap in a direction of the outer edge.
 5. Pneumaticallyoperated disk brake according to claim 4, wherein the weakened lines areformed by indentations.
 6. Pneumatically operated disk brake accordingto claim 1, wherein the covering cap does not protrude with respect tothe outer surface of the flange.
 7. Pneumatically operated disk brakeaccording to claim 1, wherein the covering cap is inserted in the flangeopening of the caliper such that, after the mounting of thecompressed-air cylinder, as a result of the extension of the plungerrod, the covering cap is torn open along the desired breaking points. 8.Pneumatically operated disk brake according to claim 1, wherein thecovering cap is force-lockingly inserted into the flange opening. 9.Pneumatically operated disk brake according to claim 1, wherein thedesired breaking points are situated at an identical angular distancefrom one another.
 10. Pneumatically operated disk brake according toclaim 1, wherein the covering cap has a ring-shaped elevation adjoiningends of the desired breaking points pointing towards an outercircumferential surface of the covering cap.
 11. Pneumatically operateddisk brake according to claim 1, wherein an outer edge area of thecovering cap has a U-shaped cross-section having an open side, relativeto the installed condition, directed toward the brake disk, and furtherwherein a metallic reinforcing ring is inserted into the U-shapedcross-section of the outer edge area.
 12. Pneumatically operated diskbrake according to claim 1, wherein the desired breaking points areformed by indentations.
 13. Pneumatically operated disk brake accordingto claim 1, wherein a center area of the covering cap having the desiredbreaking points is offset with respect to the outer surface of theflange in a direction of the brake disk.
 14. A disk brake caliper havingan interior space, comprising: a mounting flange upon which an operatingmember is mountable, the mounting flange bounding a flange opening tothe interior space; a covering cap inserted into the flange opening toseal-off the flange opening to the interior space of the caliper, thecovering cap being initially closed and having arranged therein desiredbreaking points.
 15. The disk brake caliper according to claim 14,wherein the desired breaking points are in the form of weakened lines,which weakened lines extend from a center area of the covering captoward peripheral edges thereof.
 16. The disk brake caliper according toclaim 15, wherein the covering cap is substantially circular.
 17. Thedisk brake caliper according to claim 16, wherein the weakened lines arearranged at a substantially identical angular distance from one another.18. The disk brake caliper according to claim 14, wherein the coveringcap is arranged within the flange opening so as not to protrude withrespect to an outer surface of the flange.
 19. The disk brake caliperaccording to claim 14, wherein the covering cap is force-lockinglyarranged in the flange opening.
 20. The disk brake caliper according toclaim 14, wherein the covering cap is made of an elastic material.
 21. Adisk brake assembly, comprising: a caliper having an interior space anda mounting flange, the mounting flange bounding a flange opening; acovering cap arranged within the flange opening to seal-off the flangeopening to the interior space, the covering cap being initially closedand having arranged therein desired breaking points; an operating membermounted on the mounting flange, said operating member having a plungerrod that engages with an actuating member arranged in the interior spaceof the caliper to operate the disk brake assembly; and wherein saidplunger rod tears open the covering cap along the desired breakingpoints when first operated to break the seal and engage the actuatingmember.
 22. A method of sealing a disk brake caliper having an interiorspace and a mounting flange bounding a flange opening of the caliper,the method comprising the acts of: forming an initially closed coveringcap with desired breaking points; force-lockingly inserting the coveringcap into the flange opening to seal-off the flange opening to theinterior space; and transporting the caliper with the inserted coveringcap.
 23. The method according to claim 22, further comprising the actsof: mounting an operating member on the mounting flange, said operatingmember having a plunger rod; and tearing-open the covering cap uponinitial operation of the operating member to break the seal and extendthe plunger rod through the covering cap into the interior space of thecaliper.